The invention relates to a switch for a transport system, in particular for a gravity roller table, wherein the switch is susceptible between a straight position and a deflection position for deflecting of transport materials from a main conveyor to a side conveyor branching of the main conveyor.
A transport device with a switch is known from the European patent application EP 0311699 A1, which transport device exhibits modules of roller bodies. The roller bodies here form a plane with the remaining transport rollers and can on the one hand form a linear transport unit together with the predisposed to transport rollers, on the other hand can be rotated by rotation around their own vertical axes relative to the linear transport unit. If the transport material is to be deflected to the branching lateral conveyor, then the roller bodies of the switch are turned corresponding to the outward transfer angle. In case transport materials with a large floor face are transported, then only a small part of the weight of the transport material is supported on the roller bodies of the switch, such that the deflection forces cannot prevail or cannot reliably prevail relative to the forces of the main conveyor operating in the transport direction. Either a failure of the switch or an uncontrolled rotation of the transport material can result therefrom, which in turn can lead to a back-up of the transport, in case the transport material cants at an unfavorable position of the roller track.
A transport device has become known from the European printed patent document EP-A-0251391 exhibiting a fork, where a roller body with a vertical rotation axis is supported in the fork. A vertically running bearing bolt is disposed at the fork wherein the bearing bolt is introduced into a bearing bush, such that the fork is rotatable around the axis of the bearing bolt. The front face of the bearing bush on the side of the fork exhibits at recess. The bearing bolt exhibits a horizontally projecting cross bolt below the fork, wherein the cross bolt carries a roller rotatable around the cross bolt, wherein the roller engages into the recess of the bearing bush upon a certain position of the fork such that the fork is lowered in this position and is lifted up of this position upon a rotation of the fork.
A deflection device for a transport band has become known from the U.S. Pat. No. 4,598,815 A, which comprises the series of driven swivelable rollers. The deflection device is furnished with a lift mechanism, wherein the lift mechanism can lift and lower the rollers, and a swivel mechanism synchronized with the lift mechanism, wherein the swivel mechanism swivels the rollers during each lift process into a deflection position and during each lowering process into a straight position.
It is an object of the present invention to furnish a good and reliably functioning switch for a transport system, wherein the switch can be produced cost favorable and wherein a retrofitting of existing transport systems with this switch is possible in a simple matter.
This object is obtained according to the present invention by a switch for a transport system in particular for a gravity roller table, wherein the switch is transposable between a straight position and a deflection position for deflecting of transport materials from a main conveyor to a lateral conveyor branching from the main conveyor, comprising a group of roller bodies with horizontally running rotation axes, wherein the roller bodies are disposed rotatable at in each case one fork around their rotation axes and wherein each fork exhibits a bearing bolt disposed projecting vertically downwardly from the fork, wherein the bearing bolt is introduced from the top into a vertically disposed bearing bush open on the top of a bearing block not participating in the swivel motion, such that the fork is the swivelable between a first position and a second position around the vertical swivel axis, wherein the switch is disposed in the straight out position in case the forks are in each case disposed in the first position, and wherein the switch is disposed in the deflection position when the forks in each case are disposed in the second position, wherein the forks are lifted such by a lift mechanism during the swiveling from the first position into the second position such that the transport materials during passage of the switch are lifted by at least one of the roller bodies at least partially relative to the transport system, characterized in that
either the fork exhibits a head plate disposed in the upper end region of the bearing bolt and exhibiting recesses at the bottom side of the head plate and wherein the wall of the bearing bush (24) is limited on the top by an upper front face exhibiting projections, wherein the bearing bolt is introduced from the top into the bearing bush for a swivelable support of the fork around a vertical axis and wherein the lower side rests on the upper front face, wherein the projections and the recesses are disposed such that projections engage into the recesses into the first position of the fork and do not engage into the recesses in the second position of the fork such that the fork is disposed in a lifted position by the depth of the recesses or the height of the projections in the second position relative to the position of the fork in the first position,
or the fork exhibits a head plate disposed in the upper end region of the bearing bolt, wherein the lower side of the head plate is planar and inclined relative to the horizontal, and wherein the wall of the bearing bush is limited on the top by a plane front face disposed inclined relative to the horizontal, wherein the bearing bolt is introduced into the bearing bush from the top relative to the support of the fork swivelable around a vertical axis and wherein the lower side rests on the upper front face, wherein the spatial position of the lower side and of the upper front face are such oriented relative to each other that the fork is disposed in the second position in the lifted position relative to the position of the fork in the first position,
or the bearing block exhibits recesses and the fork exhibits a rotary plate with the projections, wherein the rotary plate rests on the upper front face of the bearing bush and wherein the projections engage the recesses in the first position of the fork and wherein the projections rest outside of the recesses on the bearing block in the second position of the fork such that fork is disposed in the lifted position in the second position relative to the position of the fork in the first position by the depth of the recesses or by the height of the projections.
The rotation axes of the roller bodies are disposed perpendicular to the longitudinal direction of the main conveyor in the straight out position of the switch according to the present invention, wherein the roller bodies are disposed preferably in the plane together with the remaining transport plane of the main conveyor and serve for the straight line transport of the transport material along the main conveyor.
However the rotation axes of the roller bodies run in the deflection position such that transport material is deflected on the lateral conveyor. The roller bodies are here lifted relative to their position in a straight out position of this switch according to the present invention and the roller bodies project upwardly above the remaining transport plane of the main conveyor according to the present invention such that the transport material is at least in part lifted upon passage of the switch, wherein advantageously an increased support forces generated between transport material and roller body relative to the straight out position and wherein thus deflection force of the roller bodies becomes effective in this position of the switch to an extended measure.
The result is a direction precise deflection of the transport material even in case of high transport speeds.
The forks with the roller bodies carried by the forks are brought into such lifted position projecting above the remaining transport plane by a lift mechanism, wherein the lift mechanism becomes effective during the changing of position of the switch from the straight out position into the deflection position. The lift motion of the forks required for this purpose is derived immediately from the swivel motion of the modules from the straight out position into the deflection position with the aid of the lift mechanism such that the lift motion is performed into the deflection position based on the swivel motion of the forks. The lift mechanism forming the basis here is advantageously very simple and is realizable with small constructive expenditures.
The fork exhibits a vertically disposed cylindrical bearing bolt. The swivelable support of the fork here is performed with the aid of a bearing block placed at the transport system, wherein the bearing block comprises a bearing bush with a horizontally running and on the top open cylindrical bore-hole and an attachment base, wherein the attachment base is connected to the bearing bush and serves for attachment of the bearing bush to the transport plant. The bearing bolt is received around its vertical axis in the bearing bush such that the fork and thereby also the roller body carried by the fork are supported swivelable around this axis.
The device group comprising the bearing block, the fork and the roller body is designated in the following as module.
An advantage of the described construction of the modules comprises a simple way of production and a thereby cost favorable production. A further advantage of the described construction of the modules comprises that the forks can be exchanged in a simple manner against such forks with other roller bodies. A retrofitting of the switch, for example to transport goods with the special properties such as for example of a particular high weight can be performed not only quickly and with little expenditure in this manner but the same switch with in each case suitable roller bodies can be employed for different transport systems if required, which equals to a building block principle.
Preferably a suitable adjustment device serves for changing the position of the switch according to the present invention between a straight out position and the deflection position. The adjustment device can be formed as an adjustment mechanism, which adjustment mechanism operates at the same time on several or all modules through a common coupling rod, wherein the coupling rod can be moved with the aid of an electrical, electromagnetic, pneumatic or hydraulic actuator or for example by a manually actuated drive.
Another possibility comprises to construct the switch such that the modules are individually adjustable by in each case a proper adjustment device, whereby there results as an additional advantage that the adjustment angle of the individual modules can be selected independent from each other if required and thus can be adapted to the special requirements or to special properties of changing kinds of transport goods.
The roller bodies do not exhibit their own drive and operate thereby as passive roller bodies in the transport system according to one embodiment of the invention. This embodiment can be suitable for example for transport systems, where the transport goods are moved at a high-speed on the transport systems or for such sections of transport systems, which are associated with a heavy drop in the transport direction.
The roller bodies exhibit their own drive and support thus actively the traction of the transport goods in particular for deflection onto the network conveyor according to another embodiment of the invention. Advantageously the roller body exhibits here a pulley, wherein the pulley is disposed recessed relative to the outer circumference of the roller body, such that the roller body can be driven by an endless drive belt, wherein the drive belt is disposed completely, including its outer circulating face, below the transport plane, and therefore does not come in contact with the transport goods. Several or all roller bodies can be driven here by a common drive shaft disposed below the transport planes through in each case a drive belt wherein the drive shaft is disposed below the modules and the support console and wherein the drive belts are led around the drive shaft.
According to a further embodiment of the invention the roller body is formed as a wheel rim, wherein the wheel rim carries at least one wheel tire operating as a running face for the transport goods. An advantage of such arrangement comprises that the wheel tire or, respectively, the wheel tires can be easily replaced in case of wear and can be exchanged easily for example against such with a different diameter for a different material or surface properties (for example wheel tires with rubber covering) if required.
Advantageously the modules can be disposed next to each other on a common support console, wherein the support console runs perpendicular to the transport direction of the main conveyor. It is advantageously achieved in this manner that a switch to be inserted into the transport system can be pre-mounted and preassembled at a suitable location, such that the mounting time for the insertion of the switch into the transfer system and thereby the for this purpose required stand still time of the transport plant becomes substantially reduced.
The invention cannot only be employed in connection with transport systems, wherein the transport systems are to outwardly transfer the transport goods, but also with such transport system wherein for example a widening, a reduction, a changing of the direction, or a parallel displacement of the transport stream is desired. The invention can also be employed in sorting plants. Complete fields of switches can be formed with the aid of the invention, wherein the advantage comprises that it is possible to react to differently large or, respectively, differently heavy transport goods without having to change expensively the transport system. The switch according to the present invention is functionally received in a transport combine.
Further advantageous embodiments of the invention are indicated in the sub claims.